Heretofore, use of a board containing a material having heat storage performance has been known, and it has also been known to use a polymer of an α-olefin having 10 or more carbon atoms as a heat storage material.
For example, patent document 1 discloses that a crystalline higher α-olefin polymer obtained from a higher α-olefin having 10 or more carbon atoms is used for a heat storage material.
Patent document 2 discloses that a cross-linked olefin polymer obtained via a reaction of an α-olefin polymer obtained by polymerizing an α-olefin having 6 or more carbon atoms with another α-olefin, with a cross-linking agent is used for a heat storage material.
Patent document 3 discloses that a material obtained by decomposing an α-olefin polymer having an average number of carbon atoms of the α-olefins constituting the polymer of 6.0 to 14 in the presence of an organic peroxide is used for lubricating oil, ink, of the like.